This is a pre-copyedited, author-produced PDF of an article accepted for publication in European Journal of Public Health following peer review. The version of record, Gilmore, AB & Hartwell, G 2014, 'E-cigarettes: threat or opportunity?: Threat or opportunity?' European Journal of Public Health, vol 24, no. 4, pp. 532-533., is available online at: http://dx.doi.org/10.1093/eurpub/cku085.